1. Field of the Invention
The present invention relates to a dual-chambered container and a method of making the container. The dual-chambered container is designed to hold a medical liquid and a dry medical material in separate chambers so that the liquid and the dry material can be intermixed on demand.
2. Prior Art
Conventional dual-chambered containers for medical uses are flexible and have a partition dividing the interior of the container into chambers. The chambers of the container are brought into fluid communication with each other by breaking the partitions. One disadvantage of these containers is that small amounts of water and/or gases can permeate through the partitions, which are made of a synthetic resin. In the case where a hygroscopic and unstable drug such as an antibiotic is held in one chamber and a solvent or diluent is held in the other chamber, even very small "interchamber" permeations of water or gases are problematic. Further, an amino acid solution such as a tryptophan solution is so susceptible to oxidation that interchamber permeation can cause problems when such solution and a sucrose or protein solution are accommodated in the same container. Thus, an effective countermeasure for preventing water or oxygen gas from penetrating the partition and affecting the drug has been needed (as proposed, for example, in Japanese Patent Publication No. 63-20550). In one proposal, an external bag accommodating the drug and the liquid together with a desiccant or deoxidant is made of an impermeable material that intercepts water and oxygen gas. The desiccant, however, absorbs water from the liquid so that the hygroscopic drug cannot be dehydrated, with the liquid being condensed to an undesirable extent. In another proposal intended to resolve this drawback, the chamber for receiving the hygroscopic or readily oxidizing drug is covered with an external wall through which water and oxygen cannot permeate. The desiccant and/or deoxidant are sandwiched between the external wall and the chamber wall (as disclosed in Japanese Unexamined Patent Publication Nos. 4-364850, 4-364851, and 6-14975).
In each prior art container the chambers for receiving the drug and the liquid, respectively, are formed integral with each other. The liquid is poured in one chamber, which is then sealed with a plug and sterilized. Subsequently, the drug is placed in the other chamber, which is then sealed and wrapped with a cover. Disadvantages inherent in these prior art containers are: (i) the chamber for the drug and the chamber for the liquid cannot be sterilized separately; (ii) both chambers, one of which is already filled with the liquid, must be sterilized and dried as a whole at first, before the sealed portion of one chamber is opened again to receive the drug in an aseptic manner, thus requiring additional labor; and (iii) during steam sterilization, the interior of the drug-receiving chamber is not exposed to vapor and, consequently, is unlikely to be sterilized sufficiently.